Electric-current-measuring instrument.



0. A. KNOPP. ELECTRIC CURRENT MEASURING INSTRUMENT.

APPLICATION FILED FEB. 7, 1911.

Patented Jan. 16, 1912.

UNITED STATES. PATENT OFFICE.

o To A. KNOPP, or OAKLAND, 'CALIFORNZIEA'.

, ELECTRIC-CURRENT MEASURIIil'G INSTRUMEN '1.

Specification of Letters Patent. Patented J an. 16, 1912. Application filed February 7, I911. "Serial No.- 607,677.

Be it known that I, O'r'ro A. KNOPP, a subject of the Emperor of Germany, and a resident of Oakland, Alameda county, California, have inveiited certain Improvements in Electric-Current-Measuring Instruments, of which the following is a specification.

One object of my invention is to provide an instrument particularly designed for measuring the current flowing in a conductor forming part of a direct current circuit, which shall beofsuch a construction as will permit of its use without requiring the cut-- ting of said conductor or the opening of the circuit 'in which it is included. r

I further desire to rovide a current measuring instrumento the general vtype To all whom it may concern: I

' above noted which shall ,he of such'construction as will permit-"of itsfremainingpermanently in operation and which may, if desired, have its parts so "arranged as to give its indications at some point distant from that part of the conductor at which. it is desired tomeasure the current flow.

Another object of the invention is' to prof vide a current measuring instrument which shall operate without consuming practically any of the energy of the circuit to which it I is applied and which shall be of simple.

and substantial construction, as wellasaccurate under conditions of use.

These objects and other advantageous ends I secure as hereinafter set forth ref-.

eren'ce being had totheaccom'panying draw: ings, in wh1ch:

' Figure 1, ma front elevation to some extent diagrammatic, illustrating a simple form of my invention, Fig.2, is a diagrammatic view illustrating my improved current measuring instrument as constructed 'to give .its indications at a point distant from that at which it is applied to the conductor whose current flow is to be measured, Fig. 3, is a modified formof my invention, and Fig. 4 is a fragmentary plan showing the construction of a part of my invention, In the above drawings, 1 represents a, transverse section of a conductor in-which" flows the electric current to be measured,

and 2 is a soft iron core the shape of ia-"i ring but having-its two endsspaced apart a suflicient distance to permit of thepasthe same, Removably mounted between the k .ofcontacts 11 and 12 which may, sage between them ofthe. current conductor 1 with whatever, insulation may'rsurround which is pivotally or otherwise movably mounted a magnetic bar or needle A; this latter being so supported that it is free to turn so as to lie parallel with the line joining the ends of. thecore'. or at rightangles to such line. Upon the core 2 is Wound a coil 5 of insulated Wire connected in circuit with an ammeter'G, a variable resistance 7, and a source of current- 8. \Vhen it is desired to utilize the levice to measure the current flow in a conductor 1, the casing 3 is removed and the core 2 is slipped over said conductor so that this latter occupies an axial position relatively thereto with the netic meridian. Said casing is then replaced in the position shown in Fig. 1, and it is obvious that the current flowingin the con= .du'ctor-inducesa flux in the said core which causes the magnet or needle 4 to assume the position illustrated. The battery or cur rent source 8' is "so connected that when the switch 9 is-closed, thecurrent flows through the coil 5 in such a direction as to tend to set up aflux in the core 2 opposing'that. set up by the current in the conductor 1 and byvarying'the amount of resistance 7' as bya'sliding contact 10, the current flowing in the said coil may bebrought to such a erablyin the form of a small casing in i point that the flux set up by it will be ex actly equal to that due to the current'fiow' in the conductor 1. The current flow in the circuit which includes the CQl l' 5, as in. dicated on the ammeter, when thefiux: set

up by the current in the conductor has been neutralized, bears a definiterelation to the I proper; calibration the ammeter-"G may be lnade to give direct readin s of such curcurrent flow in said conductor, and by rent flow. In order to in cate when the flux setup by. the coil. 5 is equal-to that set upin the ductor 1, observations are-made of the magnet or 'needle 4 which will lie in aline at right angles to theline joining the endsof the core only underv this-condition- If desired, means may be provided ,whe're- I 1 by the position of the, bar or Y needle '4 may 1015 r 2 .by the current i t coup;

be indicated. at a point, distant from the---. core 2, andforfthispurpose' I provide a pair by thebar or needle 4 as long asthere is anyf fiiix in said-core 2: The bar or needle 4 if deslred I serveas: stops, ,one of them being engaged .cuit with a current'source 'such'as the'b at teryi8 and also with an indicating-instrun1enthaving a, magnetized bar or: needle 13 and" twocoils .14 and operative thereon; thearrangement being such that the first of these -eoils is in'series with thewconjtact ll while the'sjecond is inseries with the contact 12." Each coil has'f' one terminal connected; to one terminal of the current source 8,Wh1l the'needlefor bar-4 is connected in circuit with the-1'secondterminal1of said source.

".cThel-des'ign of the indicating instrument \,13v 1 1f15-' is such that when the-needle-or bar at engages'thecontact llQthe needle or bar 18 is deflected from its centraland nor-f mal position by, reason of the current flow =in'the .coil 15, so that it is caused. to: take up; a posit-ion similar to that of said first baror needle. ;;Like w'i se when the needle 41 engages the contact 12, the coil 14 being en 7 ergized, deflects the needle 13'intoa ,cjorre-t 1. sponding'position. 'When, h'owever, by"adj 'justing the variable resistance 7-,; the flux in the core 2 has been brought practicallyvto above and-Qbelow that-necessary to'completely neutralize thelfluxin thecore 2 due to thecurrent in the, conductor 1, so-:t-hat the needle .5 may be made "first to engage with the contact-11, and'then with the conammeter 6 is t-aken'l' This, "as previously explained, is proportional to. they. current iiow in the conductor 1 ,f%which"may be ob tainted-either directly from said ammeter or by calculation from the readingjthereot.

tact 12 until at last the current flow in said c1oil.isi'ought tosuch a'pointthatboththeneedles 4 and 13 occupy their mid positions,- whereupomyas before, =-the reading of the Itfis understood that in the'ca'se of the apparatus shown in Fig.2 the needle or bar 4;.togethenwith itsycontaets Hand 12 are properly mounted in acase'or supporting structure such as that'shown in Fig.1 in order to permit of their removal vfrom the core'2 when'it is desired to placethis around a conductor whose current flow measured.

is to be Should it prove desirable to have the indicating needle or bar t and its mounting v permanently attached to the'core2, this latter may be made in two parts detachably connectedtogether so as to permitof the introduction of thelfconductor 1 withoutre guiringethe removal of said needle 4 or its mounting. Q With this idea in view the device maybe made as shown in Fig. 3, with the core 2 in two parts 2 and 2 connected contacts'f 11;

conditions of use by a latch 21. As is ob-.

ductor 1. v

without breaking the circuit in which it'is ltlOWlIlg, maybe employed if the conductor 1 -1s permanently mounted on the core-2', as

turns; around the same as indicated at 1 rangement of parts is particularly adapt;

vention, .although it is by no means confined to the samefa'nd in any. case, however, the

" '1-."1Ac'1irrent measuring instrument con- SISti Dg of anhnn'ular core having ends spaced apart to: permit of the introduction of a;qcurrentfcarrying"conductor; a device for. indicating the presence of flux in said .cuit with the winding" for causing a current flow therein; and meansffor lamount ot'saidcurrent'. c y 2 A current measuring instrument consisting of an annular pore having its ends causing a flux to be set up in said core; current actuated means forneutralizing the flux set up in the core bythe current in said .con ductorf'and means for measuring th e 'curcause such neutralization of thefiuxm I rent necessary to 3. v A current, measuring. instrument consisting 1 of an annular core having ends spaced apart to permit of the introduction of-a conductor carrying acurrent capable of 'setting'up a flux in said core; a device for indicating the presence of 'a flux in said core'tmeansfor setting up a flux in said core in opposltionto that produced by the con duc'tor withinthe same; andmeans for inproduce said opposing flux.

. QJA currentmeasuring instrument consistingof a core; andevice for-indlcatlng the carrying a current to be measured and in p0 sition to cause afiun to be set up in the core;

.a winding on the core; current varying .ineans' and a curfent measuring instrument in c1rcu1t with the said windlng; and a in by the currenttobe measured.

sisting of an annular core concentric with the conductor whose current is to be measured; said current being napable of setting by a hinge 20 and locked together under The same method of measuring a current- I for example by being given one or-more core; a'winding for the core; means in cirindicating the .dicating the amount'of current necessary to r vious, these two halves maybe separated to permit of the introduction of the con- 7o in-Fig. 3: It is understood thatsuch' an arv able "for thenonportable' forms of my in-' apparatusis manipulated as heretofore dev scribed, 1n order to ascertain the quantity spaced apartto p ermi "of the introduction of I -a current carrying conductor capable of presence ota flux in said core; a conductor vsource of current connected to produce a flux in the core opposed to that set upthere- '5. A current' mcasuringinstrument .conf' rent in thewinding in order to set up a flux in the core opposed to that set up by the current in 'the conductor; with a device for indicating the amount of current flowing through the winding when said two fluxes are equal.

6. A current measuring instrument consisting ofan annular core substantially con-' centric, with a conductor whose current is to be measured; said current being capable of setting up a flux 111 said core; a device for indlcatmg the presence offlux 1n said core;

a winding on the core with a rheostat, a

battery, and an ammeter in circuit with said winding.

7. The combination in a current measuring instrument of an annular core having its ends spaced apart to permit of the introduction of a current carrying conductor whose current is to be measured; a flux indicating device removably mounted between said core ends; current'actuated means for neutralizing the flux set up in the core by the current in said conductor; and means for measuring the current necessary to cause the neutralization of said flux.

8. The combination of a core having a winding and mounted adjacent a conductor whose current is to be measured; means for settingupin said winding a current flowing in a direction to set up a flux in the core opposed to that generated by the current in said conductor; a devicefor indicating the presence of flux in the core; means fonneasuring the amount of current flowing in the winding; and an instrument electrically connected to said flux indicating device for showing the position of its movable element.

9. A current measuring instrument consisting of a core mounted adjacent a conductor whose current is to be measured; means including a movable element for indicatingthe presence of flux in said core; an instrument electrically connected to said flux indicator for indicating at a distance the position of its movable element; a winding for the core; means for energizing said Winding to produce a flux in the core opposing that produced by the current to be measured; and

means for measuring the current in the-- winding when the flux set up by the current to be measured is neutralized.

In testimony whereof, Ihave signed m'y 3 name to this specification, in the presence of two subscribing witnesses,

OTTO KNOPP. Witnesses:

E. M. SMITH, N. W. QUINLAN.

Copies of this patent may be obtained for five cents each, by addressing the "Commissioner of Patents,

Washington, D. 0. 

